For: After the party, the penance. Just as adults are forced to endure monstrous hangovers in exchange for a little seasonal ribaldry, so children must learn that Christmas presents don't come without a price. For most children, writing thank-you letters seems like a massive injustice but one, nevertheless that parents should enforce in the name of discipline and good manners. Look on it as a cleansing ritual through which the avaricious excesses of Christmas are purged. An at atonement, if you will. What are thank-you letters if not the written equivalent of three Our Fathers and two Hail Marys? And yet, scrupulously honest children might ask their parents: is it right to lie through their teeth when thanking Auntie Jean for the repellent handknit? In this instance, yes it is. Lying should be encouraged. The resulting missive may be shallow and stilted but people seem happy to collude with the charade. Gran sends a box of noxious bathcubes; grandchild writes back charming letter. Everyone benefits. Elderly relatives are entranced by grammatically wayward nonsense scrawled on Peter Rabbit notelets; parents notch up Brownie points for demonstrating that they have raised nice polite children; while said children are likely to remain on relatives' future present list.

Against: Is there a child in existence who sits down to write thank-you letters unprompted, and of their own free will? It is a tyranny - a way of punishing children for receiving presents, and perpetuated by the sort of parents who value duty more than they value a child's obvious gratitude. And anyway, wouldn't a telephone call, a text message or email be more appropriate? The idea that adequate thanks can only be expressed on paper, over which a child must reluctantly sweat and toil, is outdated and absurd. The outcome is, invariably, a few lines of forced, insincere garbage written about presents they don't like to far-flung relatives they hardly know. The truth is that thank-you letters are not about children, gratitude or relatives; they are about a parent's desire to be seen in a good light. It is all about impressing family and friends with your grasp of etiquette, and to convey that you, the letter's co-author, are not so dumb as to think that thank you is one word.

Verdict: Most people will have read gas bills that carry more weight and depth than your average thank-you letter.